Only if it is thugging. In some places it behaves itself and it is a lovely flower.

it behaves for me so no don't pull it out. if you find it growing where you don't want it then pull it out.

Thank you so much Owdboggy and Seaburngirl,I really like the flower,so I will do as you say and keep my eye on.

I have it growing through a wall at the bottom of the garden but it never seems to spread anywhere else.

Thank you Hywel that's good to know,I bet it looks lovely growing through a wall.

Yes it does. This was in my parents' garden growing through an old stone wall and it looked lovely, but I brought some up here and have it growing in between some concrete blocks ! :D
it still looks nice though.

Hywel ,it sounds lovely,and how nice to have it from your parents garden.I will definately keep it.

It does cover ground fairly quickly but can be controlled by pulling.

Thank you Norfolkapple,I am going to give it a tidy up tomorrow.